Loud-speaker diaphragm with stiffening struts



June 27, 1950 J H ss N 2,513,171

LOUDSPEAKER DIAPHRAGM WITH STIFFENING STRUTS Filed Nov. 26, 1948 INVEN'I'OR.

A TTORNE Y Patented June 27, 1950 LOUD-SPEAKER DIAPHRAGM WITH STIFFENING STRUTS Joseph A. Hassan, Quincy, Mass., assignor of onehalf to Fauthal A. Hassan, Quincy, Mass.

Application November 26, 1948, Serial No. 62,156

9 Claims. 1

This invention relates to a diaphragm with supporting means for a sound translating device.

The principal object of my invention is to improve upon the diaphragm of a sound translating device whereby it will more perfectly reproduce sound and preserve tonal quality.

It is especially intended to provide uniform sound response over a wide frequency range in small or relatively inexpensive radios and the like whereby the bass tones particularly, which are almost entirely lost in such radios commonly used, will be distinctly reproduced.

Another object is to provide structure that will achieve said objects, yet is inexpensive to manufacture and assemble in a loud speaker, and which does not require more cabinet space.

The foregoing and other objects which will appear as the nature of the invention is better understood, may be accomplished by a construction, combination and arrangement of parts such as is disclosed by the drawings and specification. The nature of the invention is such as to render it susceptible to various changes and modifications, and, therefore, I am not to be limited to said disclosures; but am entitled to all such changes therefrom as fall within the scope of my claims.

In the drawings:

Figure 1 is a top plan view of a sound translating device showing my diaphragm and Figure 2 is a longitudinal sectional view thereof. Figure 3 is an enlarged sectional view taken on the line 3-3 of Figure 1.

Figure 4 is a top plan view of a modified form of my said device and Figure 5 is a longitudinal sectional view thereof.

Figure 6 is a top plan view of another form of my invention and Figure 7 is a longitudinal sectional view thereof.

As illustrated, my diaphragm is used with a sound translating device having the usual instrumentalities to actuate or vibrate the diaphragm', including the usual support or magnetic frame It) embodying, at its upper portion, an inwardly extending, magnetic pole portion iii. A field pole 22, having a base portion 2 is attached to said frame I 8 and extends upwardly therefrom. A voice coil has a form 24 that surrounds said pole 22 around which is wound the usual coil winding 26. Surrounding said voice coil form 24 and attached to it is a compliance spider 28 that is cemented to said frame.

Extending from said magnetic frame i8 is an external diaphragm support or basket 30 at the outer end of which is the usual asket 3|.

A conical, apertured diaphragm 32 is attached at its small end extremit to said voice coil form 24. It has a free edge 34 shown as corrugated and extending horizontally outward, being attached to said gasket 3L In order to improve the tonal quality of my device, especially to reproduce bass tones, I provide supporting means for and within the diaphragm. Said supporting means is formed of struts 35 which are cemented or otherwise attached to said coil form 24 and extend 0ut wardly towards the larger end of said diaphragm. Attached to said struts is a supporting bar 38 extending substantially diametrically across said diaphragm and attached or in firm contact with substantially opposite portions thereof. This bar 38 may be T-shaped in cross section, as shown in said Figures 2 and 3, the head or cap portion being numbered 39 and the leg portion 48. Said diaphragm support may be made of thin metal, plastic or other firm material and it is preferably weighted as at 42 or otherwise made heavier at the center or middle portion to better control the sound vibrations, particularly to help reproduce bass tones.

In said Figure 5 I illustrate a larger conical diaphragm the smaller or inner portion of which is thinner than the larger or outer portion 46 to better reproduce the high frequencies. The diaphragm support preferably has a plurality of lower struts 48 which extend from said coil form 24 to an intermediate cross supporting bar 50 which preferably extends substantiall diametrically across said diaphragm at the inner point where the thicker portion 4'6 of said diaphragm commences, and is attached thereto. I provide two of said cross bars 50 as shown because of the larger size of the diaphragm. Said lower struts 48 preferably extend from said coil form 24 diagonally inward to about the center of said intermediate cross bars 50 as shown in said Figure 5.

Said diaphragm support also has upper struts 52 which extend from said supporting bar 5 diagonally upward and outward where they are attached or connected to upper supporting cross bars 54, preferably weighted as at 42.

These bars 54 extend substantially diametrically across said diaphragm thicker portion 46 and are attached to said thicker portion at the outer edge of the main body. Since a larger size diaphragm must be thicker or strengthened to hold its shape, as compared with a small size yond said outer supporting bars 54, whichincreases the sound amplification.v

In said Figure 7 a modified supporting means for the diaphragm is shown in which the struts 36 extend from said coil form 25 to a said cross supporting bar 38, that is weighted in the center as at 42. This bar 38 extends substantially diametrically across and is attached to said diaphragm 32 at a point-intermediate the-inner and outer end extremities'and approximately half way between the two said extremities. In this construction, which is especially adaptable to small size diaphragms, one said supporting. bar 42 has proved sufiicient to greatly improve the general tonal quality of a radio loud speaker and excellently reproduce the base tones.

In this construction said diaphragms may be furnished separately and by connecting said struts to the voice coil and attaching the diaphragm to the sound translating means of a radio or other loud speaker my invention is adaptable to used equipment.

Said diaphragm is made of flexible material such aspaper, cardboard, fiber or the like and is capable of vibratory movement, consequently the supporting member therefor is preferably made of material somewhat stiffer than that of the diaphragm such as plastic or thin metal. Diaphragms are commonly made generally conical in shape with the larger end at the'outside and the smaller end attached to the voice coil. Any diaphragm of these characteristics is referred to as conical.

What I claim is:

l. A conical diaphragm in combinat on with a sound translating device embodyinga coil, said diaphragm having a supporting memberembodying a plurality of struts separate from said diaphragm and attached to and extending from said coil. at a pointadjacentthesmall'erend ofsaid diaphragm outwardly, and'a supportingbarconnected to said struts and extending substantially diametrically across diaphragm at a point spaced outwardly from the inner: end and attached to portions of sai'd diaphragm'spaced apart and adjacent the outer edge thereof 2.. A conical diaphragm in combination with a sound translating device embcdying acoil; said diaphragm having. a supporting member embodying a plurality of struts'separate from said diaphragm and attached to' and extending from said coil at a point adjacent the smaller end of said diaphragm outwardly, and. a supporting bar connected to said struts and'extending substantially diametrically across saiddiaphragm at a point spaced outwardlyfromthe inner end'and attached to portionsof said diaphragm, said supporting bar beingproportionately heavier at its middle. portion than .at. its end" portions;

3. A conical. diaphragm in'combinaticn-with a sound'translating: device embodying a coil, said diaphragm having: a; supporting member; em-

bodying a pluralityiofistruts separatefrom said I It is cemented to said gasket diaphragm and attached to and extending from said coil at a point adjacent the smaller and inner end of said diaphragm, and outwardly, and a supporting bar, T-shaped in cross section, connected to said struts and extending substantially diametrically across said diaphragm at a point spaced outwardly from the inner end and attached to portions of said diaphragm.

4. A conical diaphragm in combination with a sound translating device embodying a coil, said diaphragm having a supporting member embodying a plurality of struts separate from said diaphragm and attached to and extending from said coil at a point adjacent the smaller and inner end towards the outer end of said diaphragm and terminating at a point intermediate the inner and outer end extremities thereof, a cross bar connected to said struts and extending across said diaphragm at said intermediate point and attached to portions thereof, and a plurality of struts extending from said cross bar-to a point at approximately the outerend extremity of-said diaphragm, and a cross bar connected to the lat-- ter said struts and extending across said diaphragm and attached'to portions thereof spaced apart at said latter point.

5. A conical diaphragm incombination with sound translating device embodying a coil, said diaphragm having a supporting member embodying a plurality'of struts separate from said diaphragm and attached to and extending from said coil at a point adjacent the smaller and inner end towards the outer end of said diaphragm and terminating at a'point intermediate the inner and outer end extremities thereof; a cross bar connected to said struts and extending across said diaphragm at said intermediate point and attached to portions thereof, and a plurality of struts extending-from said cross bar to a point at approximately the outer end extremity of said diaphragm, and a cross bar connected to the latter said struts and extending across said diaphragm and attached to portions thereof spaced apart at said latter point, said'cross bars being proportionately heavier at their middle portions than elsewhere.

6. Aconical diaphragm in combination with a sound translating device embodying acoil, said diaphragm having a supporting member. embodying a plurality of struts separate-from said diaphragm and attached to and extending from said coil at a point adjacent the smaller and inner end towards the outer end of said diaphragm and terminating at a point intermediate the inner and outer end extremities thereof, a pluralityof cross bars connected to said struts and extending across said diaphragm at said intermediate point and attached to portions thereof, and a plurality. of struts extending from saidcross bars to a point at approximately the outer end extremity of said diaphragm, and a plurality of cross bars connected to the latter said struts and extending across said diaphragm and attachedto portions thereof spaced apart at said latter point.

'7. A conical diaphragm in combination with a sound translating device embodying a 0011, said diaphragm having a supporting member embodying a plurality of struts separate from-said diaphragm and attached to and extending from said coil at a point adjacent the smaller and inner end towards the outer end of said diaphragm'and terminating at a point intermediate theinner and outer end extremities thereof, a plurality of cross bars connected to said struts and extending across said diaphragm at said intermediate point and attachedv to portionsithereof,.and.a plurality. of

struts extending from said cross bars to a point at approximately the outer end extremity of said diaphragms, and a plurality of cross bars connected to the latter struts and extending across said diaphragm and attached to portions thereof spaced apart at said latter point, a portion of said diaphragm extending outwardly in substantially the same plane as the adjoining portion thereof and beyond the latter said cross bars.

8. A conical diaphragm in combination with a sound translating device embodying a coil, said diaphragm the outer and larger portion of which is thicker than the inner portion and having a supporting member embodying a plurality of struts separate from said diaphragm and attached to and extending from said coil at a point adjacent the smaller and inner end towards the outer end of said diaphragm and terminating at a point intermediate the inner and outer end extremities thereof, a plurality of cross bars connected to said struts and extending across said diaphragm at said intermediate point and attached to said thicker portions thereof, and a plurality of struts extending from said cross bars to a point at approximately the outer end extremity of said diaphragm, and a plurality of cross bars connected to the latter said struts and extending across said diaphragm and attached to portions thereof spaced apart at said latter point.

9. A conical diaphragm in combination with a sound translating device embodying a coil, said diaphragm having a supporting member embodying a plurality of struts non-integral with said diaphragm and attached to and extendin from said coil at a point adjacent the smaller end of said diaphragm outwardly, said struts being made of different and firmer material than said diaphragm, and a supporting bar connected to said struts and extending substantially diametrically across said diaphragm at a point spaced outwardly from the inner end and attached to portions of said diaphragm spaced apart and adjacent the outer edge thereof.

JOSEPH A. HASSAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,820,137 Hanna Aug. 25, 1931 1,896,484 Dopyera Feb. 7, 1933 2,002,189 Round May 21, 1935 2,014,621 Jensen Sept. 17, 1935 

